lennon



Feb. 9, 1965 n. c. LENNON REFRIGERATOR common DEVICE Filed March 28,1961 4 Sheets-Sheet 1 Feb. 9, 1965 n. c. LENNON 3,169,179

REFRIGERATOR CONTROL DEVICE Filed March 28. 1961 4 Sheets-Sheet 2 Fig.3.

Z9 JZQMJOJ.

' Attorney.

Feb. 9, 1965 n. c.- LENNON v3,169,179

REFRIGERATOR CONTROL DEVICE Filed March 28, 1961 4 Sheets-Sheet 3 5 was25 ."I -1- 19 :5 -20! I I n u u Filed Mar. 28, 1961, Ser. No. 98,898 14Claims. (Cl. EMF-61.69)

This invention relates to control devices for refrigerators, and moreparticularly to control devices for automatically defrostinghousehold-type refrigerators and freezers.

It is well known that in household refrigerators and freezers there is atendency for frost to form on the exterior surfaces of the evaporator.The accumulation of this frost progressively lowers the efiiciency ofthe unit as the-thickness increases, since the frost is essentially aninsulating blanket surrounding the evaporator. Such frost is formed bythe admission of moist air into the interior of the refrigerator orfreezer when the door is open.

In the design of household refrigerators and freezers, it is desirableto provide a means for periodicallyand automatically removing the frostwhich is formed on the evaporator. This may be accomplished by providingan auxiliary heating means, such as for example a resistance heater,which will rapidly melt the frost formation from the evaporator when thecompressor motor has been deenergized. This particular defrostingcontrol must, therefore, deenergize the compressor motor and energizethe auxiliary heater in response to some predetermined condition orcombination of conditions and subsequently reenergize the compressormotor and deenergize the auxiliary heater.

A number of different types of automatic defrosting systems for domestichousehold refrigerators have been provided in the past. In one of thesesystems, the compressor motor is deenergized and the auxiliary heater isenergized after a predetermined number of compressor cycles. In anothersystem, provision is made for deenergizing the compressor motor andenergizing the heater after a predetermined number of openings of therefrigerator door. ()ne other system which has been used is acombination of the first two systems mentioned, wherein the compressormotor is deenergized and the auxiliary heater is energized after apredetermined aggregate number of compressor cycles and door openings.Prior art defrost controls used in these aforementioned systems havebeen found to be somewhat complicated in structure, thereby addingappreciably to the overall cost of the control mechanism. In addition,the configuration of the various complementary parts of the controlmechanism usually eventuates in a mechanism which is inflexible in itsapplication and has a relatively large configuration.

It has, therefore, become desirable to provide a defrost control whichis simple in construction and readily manufacturable, therebycontributing to a substantially lower over-all cost. It is furtherdesirable thatsuch a control he very flexible in its application andrelatively small in size. .It is additionally desirable that such acontrol be sturdy and compact.

Accordingly, an important object of my invention-is to provide animproved defrost control which due to its relative simplicity may bemanufactured at a reduced cost.

Another object of my invention is to provide a defrost control which issimple in structure and has an improved flexibility of application. 1

A further object of my invention is to provide a defrost control with animproved means for actuating a switch after a predetermined number ofcycles have elapsed.

A still further object of my invention is toprovide an improvedidefrostcontrol which is very efiicient in open ation, sturdilyconstructed, andrelatively small in size.

United States Patent ddhhd'm Patented Feb. 9, 1965 has two positions andincludes two fixed contacts engageable by a movable contact. Thesupporting arm for the movable contact is a snap acting spring memberand it has one of its ends in cooperation with a pivoted follower. Thisfollower rides upon [a rotatable switch actuating member. The actuatingmember includes a ratchet wheel portion, a hub portion with a peripheralinterruption formed thereon, and a pair of axle sections. wheel portionof the actuating member has a toothed periphery which is intermittentlydriven by a driving means to rotate the member. The axlesectionsfurnish'rotatable trunnions for the actuating member. The hubportion of the actuating member is in continuous engagement with thefollower and arranged to actuate the follower by coaction between thefollower and the interruption of the hub portion to operate the movablecontact into one of its positions. Thestructure of the switch actuatingmember is therefore such that it performs three functions in the defrostcontrol, serving as a combination ratchet wheel, switch actuatingelement, and axle means for the device. With this arrangement of theswitch actuating member in the defrost control, a compact structurewhich is flexible in application and efiicient in operation is therebyachieved. 1 i

Further aspects of my invention will become apparent hereinafter and thespecificationv concludes with claims particularly pointing out anddistinctly claiming the subiect matter which I regard as my invention.The invention, however, as to organization and method of operation,together with other objects and advantages thereof, may best beunderstood by reference to the following description when taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a plan view of an improved solenoid operated defrost controlembodying my invention, with the cover removed therefrom;

FIG. 2 is a side elevational view, partially in section and partiallybroken away to illustrate the various internal parts of the control ofFIG. 1;

FIG. 3 is an exploded view showing the various parts of the control ofFIG. 1, with the exception of the cover;

FIG. 4 is a bottom view of the control of FIG. 1;

FIG. 5 is a plan view of an improved manually operated defrost controlembodying my invention in alternate form thereof; and I FIG. 6 is a sideelevational view partially in section and partially broken away toillustrate the various internal parts of the control of FIG. 5.

Referring now to FIGS. 1 and 2, there is shown a defrost control for adomestic household refrigerator, which embodies one form of myinvention. The control 1 includes an elongated insulatingbase 3 which,for example, is formed of molded phenolic thermosetting plastic, andcover 5 which may be constructed of similar material. Base 3 and cover 5each have recesses formed therein and are suitably fastened together toprovide cavity 7 wherein the various parts of my control areexpeditiously. contained and supported.

As best shown in FIGS. 2 and 3, insulating base 3 serves as a containerfor supporting upper and lower fixed contact terminals 9. and 11,respectively, movable contact terminal 13, and solenoid terminal 15.Terminals 9 and 11 are fastened to base 3 at vertically stepped upperhorizontal walls 17 and 19 (FIGS. 1 and3) by means of barbed outer edges'21 and downwardly turned ears-23. More particularly, blade portion 25of each of the terminals 9 and ill is extended through a molded slotformed perpendicularly through one of the walls 17 and 19, such as slot27, which is illustrated representatively in FIG. 3

The ratchet.

for terminal 11. The terminals 9 and 11 are then staked to the base wall17 and 19 by means of barbed outer edges 21 which are parted to overlapbottom ends of each of the slots and engage the walls to securely fastenterminals 9 and 11 to the base 3. Ears 23 are generally parallel toblade portions 25 and extend through molded slots 29, to rigidlylaterally position the terminals 9 and 11 in the base.

Terminals 1'3 and attached to stepped base walls 31 and 33, respectively(shown in FIG. 2) by means of barbed outer edges 21 formed upon bladeportions of these terminals, the blade portions being extended throughthe wall slots in the same manner as described for terminals 9 and 11.Detent holes 35 are formed in the various blade portions 25 of theterminals 9, ll, 13, and 15 for engagement with an associated quickconnecting terminal. Movable contact terminal 13, as illustrated, hastwo blade portions 25 to facilitate its attachment to two associatedquick connecting terminals.

Turning now to a discussion of the switching mechanism of my improveddefrost control 1, as shown in FIGS. 1 and 2, the upper and lower fixedcontact terminals 9 and 11 are generally L-shaped to include horizontalsupporting sections 38 and 40 which are parallel to each other andseated on the top surfaces of horizontal walls 17 and 19. Sections 38and 49 have fixed contact buttons 37 and 39 attached respectivelythereto. To furnish a pivotal support for a snap acting switch mechanismis defrost control 1 and also to support in cantilever fashion a motiontransmitting follower member which efficiently actuates this switchmechanism in response to predetermined conditions, movable contactterminal is specially constructed, as shown in FIGS. 2 and 3. Moreparticularly, terminal 13 includes an aforementioned pair of parallelblade portions 25 which are connected together by bight 41 to form aU-shaped terminal portion. Bight 41 has a lateral extension 43 (FIG. 3)formed thereon which serves as a base for a T-shaped platform section 45connected thereto by upright section 47. Extension 43, platform section45 and upright section 47 thus form a U-shaped switch supportingportion, as shown in FIG. 2. To attach the snap acting switch mechanismand follower member to terminal 13, a conductive metal post 49 isprojected outwardly and upwardly in edgewise fashion from wing 51 ofplatform section 45. As shown in FIG. 3, post 49 has the configurationofan inverted T, the bottom of which is extended through a slot (notshown) of platform wing 51 and staked thereto. Transverse notches 53 areformed in vertically oifsetrelationship on opposite lateral sides of thecentral upright portion 55 of post 49. These notches serve to pivotallysupport a snap-acting switch member, as shall become apparenthereinafter.

The snap-acting switch mechanism for my improved defrost control itincludes a leaf-type-spring member 57 which serves as a resilient bladefor supporting a twosided movable contact button 59. Strip member 57 ispreferably composed of a resilient or spring-type conductive metal, suchas beryllium copper. For an understanding of the structure of member 57,attention is directed to FIGS. 1 and 3. Strip member 57 includes threegenerally parallel arms til, 63, and 65, all joined together at bothends, and with the central arm 63 being split into two longitudinallyextending sections 63a and 63b, respectively. One end 67 of the stripmember 57 carries movable contact button 59 while the other end 69 hastongue 71 formed thereon. Tongue 71 of member 57 serves to actuate theswitch in response to predetermined conditions, as shall be described indetail hereinafter. The other arms 61 and are pressed into a corrugatedor undulating configuration, as shown in FIGS. 2 and 3, in order toproduce an end-to-end tension in the member 57. The inner ends 64a and64b of the two sections 63a and 63b of the central arm 63 fit withinvertically offset notches 53 on opposite sides of central uprightportion of the inner ends of the sections 63;: and 63b with notches 53,the strip member 57 stresses and pivots to provide snap action of themovable contact button 57 between its two switching positions inresponse to actuating forces exerted upon tongue 71.

Turning now to an important aspect of my invention, whereby l haveprovided a simplified and efficient means for actuating the contacts ofmy switch in response to predetermined conditions, as further shown inFIGS. 2 and 3, a channel-shaped follower 73 is also attached to andsupported by the movable contact terminal 13. More specifically, thefollower 73 has its supported end portion 75 extended underneath thebase of post 49 betwee post and platform section 45, with the extremeend 77 of follower 73 being turned upwardly to the left of post 59(viewing FIG. 2). Follower 73 is thus mounted in cantilever fashion bysandwiching its supported end 7:3 between post 49 and platform section45. As shown in FIGS. 1 and 2, the right half of spring member 57 thenoverlies a portion of follower 73. The other end 79 of follower 73 isturned downwardly, as shown in FIG. 3, to form depending actuating tooth81. Between ends 75 and 7'9 of follower 73, an upright tab 33 is formed.Tab 83 extends perpendicularly upwardly from principal surface 89 of thefollower 73 and includes a transverse elongated slot 85 through whichtongue 71 of snap acting member 57 is extended. By means of thecooperation of tongue 71 with slot 85, condition responsive forces aretransmitte to member 57, as shall become apparent hereinafter. Betweentab 83 and the toothed end 79 of the follower 73, an aperture is formedin the principal surface 89 midway between the flanged longitudinalsides 91. A pair of slots 93 are also disposed on opposite sides ofaperture 87 between the aperture and the flanged sides 91. Aperture 37receives an adjustable screw for a motion transmitting plunger ofbellows assembly 95. The purpose of slots $3 is to fasten a U-shaped nut97 to follower 73, for threaded engagement with the adjustable screw.Further aspects of the transmission of condition responsive force tofollower 73 by bellows assembly shall be described hereinafter.

Follower 73 is supported in cantilever fashion upon terminal 13 so thatslot 85 of tab receives tongue 73 of movable contact member 57, andactuating tooth $1 is biased in a radial direction toward the axis ofrotation of switch actuating member 9) This biasing effect is caused bystressing the end '79 of follower 73 upwardly (viewing FIG. 2) from afree position, to impart a spring action to the follower.

To enable switch actuating member 99 to efficiently perform threeimportant functions in my improved defrost control f, it is essentiallyof tripartite construction. More particularly, the switch actuatingmember comprises a ratchet wheel portion ltd a hub portion M92 includingsections 363 and Mi l, and an axle portion includina sections and 107.The ratchet wheel portion Trill of member 99 has an annularconfiguration with a series of teeth 109 formed on the outer peripherythereof. These teeth are intermittently driven by an electricallyenergized mechanism, as shall be described in detail hereinafter. Hubsections res and 1534 are formed integral to ratchet portion fill oneach side ll'lSicGf respectively, and are concentric and adjacentthereto. To actuate follower 73 in response to rotation of member .99,an elongated slot 111 is formed in the outer cylindrical surface of hubsection 1%, in parallel disposition to the axis of member "91. 'Axlesections 105 and 167 project outwardly from the outer ends of hubsections 11% respectively, and are concentrically arranged with relationto ratchet portion fill and hub sections lltlE-i, 94. The axle sectionis connected to hub section ti -3 by an intermediate hub section oflesser diameter. Axle sections 1115 and 1117 are rotatably supported inopposed bearing recesses 113 formed on the inner walls of base 3. Toaccurately and efiiciently seat the rotatable sections of the switchactuating member in recesses 113, rear surfaces 114 thereof are slopeddownwardly and toward the terminal end of base 3, as shown in FIG. 3,

T o explain the manner of actuation provided by my improved switchactuating member Wand its coaction with follower '73 for operating thecontacts of the de frost control switch, attention is directed to FIG.2. V The driving assembly for defrost control 1 comprises an elongateddriving member 115, pawl 121 which is. attached thereto, and anelectrically energizable solenoid mechanism 125. Driving member 115 ismounted in cantilever fashion to a bottom wall of base 3 by fasteningrivet 119 through end 117 of member 115 and to 1 the base. U-shapedhairpin-type pawl 121 is extended through slot 120 of member 115 and hasthe bottom ends 122 of its sides turned over, as shown by dotted linesof FIG. 3. Pawl 121 is attached to driving member 115 intermediate thelongitudinal ends thereof by extending bottom ends 122 of the pawlthrough lanced channels 124-. Pawl 121 serves to intermittently driveactuator 99 in defrost control 1. More specifically, the pawl 121brackets a segment of the cylindrical ratchet wheel portion 101 (asshown in FIG. 2) and the outermost bight port-ion 125 (FIG. 3) of thepawl intermittently engages consecutive ratchet teeth 1119 to drivemember 99 in a clockwise direction (viewing FIG. 2) in step-by-stepfashion.

V The actuating tooth 81 of follower 73 normally rides upon the smoothouter periphery of hub section 103;

With tooth 8 1 of the follower 73 in such a position, the snap actingmovable contact member 57 is normally biased so that itsmovable contactbutton 59 engages upper fixed contact button 37. With the switch ofdefrost control 1 in this position, a circuit may be closed throughterminals 9 and 13 via conductive post 49 to maintain the compressormotor of a refrigeration system in an operative (i.e. energized)condition. Each time driving member 115 pivots downwardly through asmall angle and'in a clockwise direction of rotation from the positionwherein it is shown in FIG. 2, bight section 125 of pawl 121 drivesswitch actuating member99 about its axle sections 1115 and 107 one toothin a clockwise direction of rotation. After a predetermined angularrotation of member 99, tooth 81 of follower 73 reaches slot 111 of hubportion 103. Actuating tooth 81 thereupon enters slot 111. As the freeend of follower '73 pivots downwardly towhere it is shown in FIG. 2,slot 85 of the follower carries its cooperating tongue 71 of switchmember 57 with it and thereby snaps tongue '71 of the movable. contactmember 57 in a clockwise direction about post 49. Movable contact button59 is thereupon rapidly moved out of engagement with upper fixed contactbutton 37and pivots itself in a counterclockwise direction of rotationabout notch 53 and into engagement with lower fixed contact button 39.(See EEG. 2.) This is the defrosting position for control 1 and acontrol circuit to a suitable defrosting heater maybe connected throughlower fixed contact terminal 11 and movable contact terminal 13. Tocontrol the rotative movement of switch actuating member 99, detentstrip 126 is fastenedto an internal Wall of base 3 by screw 12619. Thefree end of strip 126 is "disposed in continuous frictional engagementwith the periphery of hub section 193 to thereby control the rotativemovement of member 99. i

To intermittently pivot driving member 115 upon its cantileveredsupporting end 117 and thereby step switch actuating member 99, in thedefrost control 1, I have provided the aforementioned solenoid mechanism123. Solenoid mechanism 123' includes a substantially U- shapedsupporting frame 127, bobbin 129 which fits within the frame, and coil131 which is wound around bobbin 129 andproperly insulated. An apertureis formed in the top portion 133 of frame 127. Neck 135 of a suitablyconfigured core 137 is extended through the aperture of top portion 133,as shown in FIG. 2, and an annular flange 139 of the core is turned overon the outer surface of top portion 133 to fasten the core in its properposition. To help position top portion 133 of frame 127 relative to theadjacent inner surface of cover 5, a shallow U-shaped retainer spring 111 is also attached to the frame by being sandwiched at its centerbetween flange 139 and top portion 133. Spring 111 provides outstretchedarms, the free ends of which resiliently engage the inner surface ofcover 5. The cylindrical surface of core 137 is fitted within the axialbore of bobbin 129, as shown in FIG. 2. Core 137 has a suitable annularpole shader 143 positioned in an annular groove on the bottom 14 thereof(viewing PEG. 2). Cylindrical plunger 145 is positioned to reciprocatewithin the bottom of the bore of bobbin 129 (viewing FIG. 2) and isextended through an aperture in the frame. Plunger 1-4-5 has a dependingstud section which is shaped to provide a cylindrical surface 14*? ofreduced diameter which extends outwardly from the bottom 146 of plunger145 and an outermost end 151 of increased diameter. To operatively linkplunger 145 to pawl 121, the elongated driving member has a keyshapedslot 153 (PEG. 3) formed therein for receiving reduced diameter surface149 of plunger 145. More particularly, the depending stud section ofplunger 145 is extended through an enlarged entrant portion of slot 153and the reduced diameter surface 14% is then moved laterally toward theend 155 of member 115 until the parallel sides of slot 153 are disposedvertically between outermost end 151 and bottom 146 of the plunger. isturned upwardly from end 155 of member 115 and inserted through thebottom of compression spring 159. The upper end of compression spring159 isseated within a suitable recess provided by bottom portion 161 offrame 127. Spring 1519 biases end 155 of member 115 away from thesolenoid coil, as shall be described in detail hereinafter.

Turning now to a discussion of the operation of driving member 115 inresponse to energization and deenergization of solenoid mechanism 123,attention is directed to FIG. 2. The solenoid coil 131 may have one ofits ends connected to fixed contact terminal 9 and the other of its endsconnected to solenoid terminal 15. Terminals 13 and 15 may then, forexample, be connected in series With contacts of a suitable switch thatis normally open and either closes when the refrigerator door is opened,or closes when the compressor motor is deenergized. It will beunderstood by those skilled in the art that the solenoid coil 131 mayalso be connected in a circuitso that it becomes energized anddeenergized in response to the total number of times in which thecompressor motor is deenergized and the refrigerator door opens.

When the solenoid coil 131 is energized, plunger 145 is attracted intothe bore of solenoid bobbin 129 and is in the position wherein it isshown in FIG. 2. In this position, spring 159 is held in compression byshoulder 152 of plunger 145 bearing against the driving member 115 andmember 115 has just moved pawl bight into a driving position instraddling engagement with one of the ratchet teeth 1119 ofv switchactuating member 99. When the solenoid coil 131 is then thereafterdeenergized, the plunger is released and spring 15? expands to pivotfree end 15.5 of member 115 about its cantilevered support. Hairpin pawl121 then drives the switch actu ating member 99 onetooth in a clockwisedirection (viewing FIG. 2). Aftera predetermined number of compressorcycles or door openings commensurate with the number of ratchet teeth15% of member 959 have thus been counted, actuating tooth 81 then movesinto slot 111 of the hub portion 1113 and movable contact 59 toggles outof engagement with fixed contact 37 and into engagement with its fixedcontact 39.

To provide'a'means for adjusting the pivotai stroke Tab 157 arca es ofdriving member 113, adjusting screw 163 is shown in threaded engagementwith a bottom wall of base 3 and is engageable with the adjacentunderside of driving member 115. (See PEG. 2.) Screw 1&3 may also beplaced in threaded engagement with the aperture underlying end 151 ofthe plunger 145 to vary the stroke thereof.

To return the movable contact 59 into engagement with its upper fixedcontact 37, after it has been in its defrost position (i.e., inengagement with contact 39) and thereby deenergize a defrosting heater,1 have provided the aforementioned bellows assembly 95. Turning now toan explanation of bellows assembly $5, as shown in FIGS. 2 and 3,bellows cup or housing 165 serves to support and contain bellows 167.Bellows cup 165 includes upwardly extending flanged sides 169 forstraddling oppositely disposed stepped walls 171 on the bottom of base3. Sides 1 59 of cup 16:3 engage stepped walls 1'71 and are held rigidlyin position against these walls by means of tabs 173 which are insertedinto appropriate receiving slots 175 in the bottom wall of base 3 andthen turned over against an inner surface as shown in PEG. 1.

Bellows cup 165 also includes a depending flange 177 (FIG. 3) withprojecting arm 179 extending therefrom for supporting capillary 1551.Capillary 181 is connected to a suitable bulb 103 and contains athermally responsive fluid, such as methyl chloride ordichlorodifiuoromethane.

For furnishing the temperature responsive actuating force to return themovable contact 59 of defrost control 1 to its normal or nondefrostingposition (i.e., into engagement with contact 37), bellows 167 is mountedwithin and supported by the bellows cup 165. A restraining annulus 185is attached to cup 155 to restrict upward movement of bellows 167. Toprovide a transmission area for the temperature responsive force,bellows 167 has a central cup-shaped recess 187. Recess 187 bearsagainst the semi-spherical bottom 189 of pushrod 191. Pushrod 191 isconstructed of a plastic material and its upper end has a cup shapedrecess 132 with a conical seat 192a formed therein for engagement withadjustable screw 193. More particularly, screw 193 is in threadedengagement with bight section 195 (FIG. 3) of U-shaped nut 97. From eachside of bight section 195 of nut W, an arm 197 is extended upwardlytoward cover 5 (as shown in FIG. 2). The arms 197 are parallel to eachother and each arm has a finger 195 The fingers 199 are extended throughslots 93 of follower 73 and lapped over (as shown in FIG. 1) to securenut 97 to the follower. Screw 193 is extended through aperture 87 offollower '73 and its pointed bottom 1921) engages seat 192a of pushrod191 in swivel like fashion. With nut 97 in threaded engagement withscrew 193 attached to the follower 73 (FIG. 2), engagement of thepointed bottom 19211 of the screw with the pushrod forces bottom 189 ofthe pushrod 191 toward the bottom of cupshaped recess 187 of the bellows167. When the movable contact 59 is in engagement with upper fixedcontact 37, the pointed bottom 1925 of screw 193 is spaced slightly fromthe bottom of seat 192a and pushrod 1 11 therefore has no affect uponfollower '73. After the movable contact 59 has been snapped downwardlyinto engagement with defrost contact 39, however, the compressor motoris deenergized, a defrosting heater is energized, and the temperature ofthe'capillary or bulb (which would, of course, be properly positioned inthe unit to sense temperature), then starts to increase. As a result ofthe increased temperature of the bulb, the vaporization of some of thefluid therein causes the bellows internal pressure to increaseaccordingly. After the temperature has risen to a predetermined value,the bellows moves pushrod 131 upward from the position wherein it isshown in FIG. 2 and screw 193 is accordingly engaged by pushrod seat192ato pivot the follower in a counterclockwise direction of rotation.Slot 85 of follower 73. then acts upon tongue 71 and forces movable {5contact 59 out of engagement with defrost contact 39 and into engagementwith upper fixed contact 37.

To facilitate the adjustment of the bellows pressure exerted uponfollower 73, a suitable aperture 194- is formed in cover 5 above thenotched outer end of adjustable screw 193. Aperture 194 allows access toscrew 193 for purposes of adjustment thereof after cover 5 has beenassembled to. base 3.

To calibrate the trip position for the switch with relation to theactuator 99 and assure that the tooth 81 of follower 73 will move out ofslot 111 of actuator 09 before movable contact 59 moves out ofengagement with defrost contact 39 and into engagement with contact 37,screw 201 has been provided. Screw 201 has its slotted head outside oneof the walls of base 3, as shown in FIG. 2, and its inner end is inthreaded engagement with L-shaped tongue 203 of terminal 13. Forcalibrating the trip position for the switch, with the movable contact59 in its defrost position (i.e. in engagement with contact 39), asuitable shim (not shown) is inserted between the smooth periphery ofhub section 103 and the bottom tip of tooth 81. Screw 201 is thentightened into engagement with terminal tongue 203 until movable contact59 moves into engagement with fixed contact 37. By adjusting screw 201in this manner, it has been found that if the switch is in the defrostposition and bellows pushrod 191 acts upon follower 73, when tooth 81moves out of slot 111, the solenoid coil still being deenergized, spring159 moves the free end 155 of driving member 115 downwardly to stepratchet wheel portion 101 of the actuator before the movable contact 59engages fixed contact 37. In my defrost control 1, screw 201 thusprovides a simple and efficient means for calibrating the trip positionof the switch with relation to the'actuator It will now therefore beseen that I have provided a new and improved defrost control which isvery simple in construction and has an improved flexibility ofapplication. This control provides an efficient means for automaticallycontrolling defrost in a household-type of refrigerator. By providing aswitch actuating member which performs three important controllingfunctions, a very effective and low cost means for actuating the switchcontacts and counting cycles has been thereby achieved. My defrostcontrol 1 also incorporates a very effective means for snapping theswitch contacts between their two positions in response to temperatureand also in response to an electrical actuating device.

FIGS. 5 and 6 illustrate, as an alternate embodiment of my invention, amechanically operated defrost control 205. This particular defrostcontrolling device is specially designed to initiate a defrosting heaterafter a predetermined number of door closures have been counted. Control205 may therefore, be mounted so that it is mechanically operated by arefrigerator door. For defrost control 205, the same reference numbershave been employed to indicate switch parts which have heretofore beendescribed for control 1. Parts which have a modified structure incomparison to the structure of their correlative parts in defrostcontrol 1 but perform the same basic function in the control 205 areidentified by the same reference numerals with the letter a suflixedthereto. The essential difference between defrost control 205 anddefrost control 1 is, of course, that the defrost control 205 isoperated by a plunger 207 instead of being operated by a solenoid.Plunger 207 may be constructed of molded plastic material and itincludes acylindrical guiding portion 209 which reciprocates in aprojecting guiding aperture 211 formed in cover 5a. Plunger 207 alsoincludes shank 213, an annular rim 215 which is formed near the bottomof shank 213 (viewing FIG. 6), and depending frusto-conical projection217. Shank 213 of plunger 207 is'extended through the bifurcated freeend 219 of driving member 221. (See FIG. 5.) To nor mally bias plungerv207 to its outermost position spring 223 runs in compression between abottom wall of base the bottom wall of base 3a.

3a and the annular bottom shoulder of rim 215 of the plunger. Bottom 225of spring 223 is laterally positioned in recess 227 which is formed onthe inner surface of Top 229 of compression spring 223 surroundsdepending projection 217 of the plunger and is thereby laterallypositioned with respect to and in engagement with the plunger 207.

To explain the operation ofthe plunger operated defrost control 205,attention is directed to FIG. 6. When the outermost end 231 of'plunger207 is depressed, the bifurcated free end 219 of driving member 221 ispivoted downwardly about its cantilivered support due to the biasingforce imparted thereto and hairpin pawl 121 drives switch actuatingmember 99 in a clockwise direction in the same manner as previouslydescribed for defrost control 1. After a predetermined number of cyclessuch as for example refrigerator door closures have been counted,actuating tooth 31 enters slot 111 of the switch actuating member 99 tomove movable. contact 59 out of engagement with contact 37 and intoengagement with defrost contact 39. The bellows assembly 95 thereafteracts upon follower 73 in the same manner as previously described fordefrost control 1. It will therefore, be seen that notwithstanding thefact that defrost controls 1 and 205 incorporate different intermittentdriving means, they operate in essentially the same manner and alsoincorporate a multiplicity of interchangeable parts.

To enable the mechanically operated defrost control 205 to be used foroperating appliances, such as an electric fan, and an illumination meansin response to each reciprocation of the plunger 297, additionalterminals 231 and 233 are provided. Each of these additional terminalsmay control a circuit connected across it and terminal 15, throughconductive driving member 221. Terminal 231 comprises two integralL-shaped sections 231a and 231k (see FIG. 6). Section 231a is suitablyfastened to the bottom wall of base 3a and includes a verticallyextending outer blade portion for receiving an external connection.Section 2321b has an elongated vertical portion which terminates ina.horizontally disposed fixed contact portion 235. Terminal 233 isL-shaped and includes an elongated vertical section with a blade portionformed thereon and a horizontal section 236 which is riveted to the topof raised portion 237 of base 3a. The horizontal section 236 of terminal233 has an elongated transverse section 239 as shown in FIG. 9 which hasa fixed contact indentation 240 for cooperation with driving member 221when the driving member is in its uppermost position (FIG. 6). Stud 241is threaded into engagement with a lanced aperture 243, and the bottom245 of this stud engages fixed contact section 235 of terminal 231 whendriving member 221 is in its down position (viewing FIG. 6). It willtherefore be seen that terminals 231 and 233 provide an efiicient meansin control 205 for controlling at least two additional circuits inresponse to reciprocating movement of plunger 207. a

The simplicity of structure, etiiciency of operation, and flexibility ofapplication of my improved'defrost control will now therefore becomeapparent and as a result of this simplicity, the defrost controls whichform the illustrative embodiments of my invention are relativelyinexpensive to manufacture.

While in accordance with the patent statutes, I have described what atpresent are considered to be the preferred embodiments of my invention,it will be obvious to those skilled in the art that various changes andmodifications may be made therein without departing from the invention,and I, therefore, aim in the following claims to cover all suchequivalent variations as fall within the true spirit and scope of theinvention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is: I

l. A refrigerator control comprising'a'switch movable between twooperating positions, follower means for moving said switch between itsoperating positions, a unitary hub portion with an axially extendingperipheral interruption formed thereon, and an axle means, said portionsbeing concentrically arranged for rotation upon said axle means, meansfor intermittently driving said switch actuating member, said ratchetwheel portion having a toothed periphery driven by said driving meansthereby to rotate said actuating member, said hub portion being incontinuous engagement with said follower means and arranged to actuatesaid follower means once during each revolution by coaction between saidfollower means and the interruption of said hub portion, whereby saidunitary switch actuating member serves as a combination ratchet wheel,switch actuating element, and rotatable journal.

2. A refrigerator control comprising a switch movable between twooperating positions, a follower for moving said switch betweenits'operating positions, a molded insulating base for supporting andcontaining said switch, a unitary rotatable switch actuating member oftripartite construction, said unitary member including a ratchet wheelportion, a hub portion with a peripheral interrup tion formed thereon,and an axle means, said portions being concentrically arranged upon saidaxle means, said axle means being journalled for rotation uponstationary bearing surfaces formed in said molded insulating base,

means for intermittently driving said switch actuating member, saidratchet wheel portion having a toothed periphery driven by said drivingmeans thereby to rotate said member, said follower being supported incantilever fashion at one of its ends and having its free end biasedradially toward the axis of rotation of said actuating member, said hubportion being in continuous engagement with the free end' of-saidfollower and arranged to actuate said follower by coaction between thefree end of said follower and the interruption of said hub portion,whereby said unitary switch actuating member serves as a combinationratchet wheel, switch actuating element, and rotatable journal.

3. A refrigerator control comprising a switch movable between twooperating positions, follower means for moving said switch between itsoperating positions, a molded insulating base for supporting andcontaining said switch, a unitary rotatable switch actuating member oftripartite construction, said unitary actuating member including aratchet wheel portion, a hubportion with a peripheral interruptionformed thereon, and an axle means,said portionstbeing concentricallyarranged for rotation upon said axle means, stationary bearing means forrotatably supporting said axle means formed in said molded insulatingbase, said ratchet wheel portion having a toothed periphery thereon, adriving member supported in cantileverfashion, said driving memberhaving a pawl means thereon, the pawl means of said driving member beingarranged to intermittently engage the toothed periphery of saidratchet'wheel portion, thereby to rotate said actuating member, said hubportion being in continuous engagernent with said follower means andarranged to actuate said follower means by coaction between saidfollower means and the interruption of said hub portion,

whereby said unitary switch actuating member serves as a combinationratchet wheel, switch actuating element, and

peripheral interruption formed thereon, and a pair of axle sections saidratchet wheel and hub portions being concentrically arranged forrotation upon said axle sections, a pair' of oppositely disposedrecesses formed in said base, said recesses eachhaving at least onesloping surface thereon and arranged to receive and support said axlesections in bearing relationship therewith, means for intermittentlydriving said switch actuating member, said ratchet wheel portion havinga toothed periphery driven by said driving means thereby to rotate saidmember, said hub portion being in continuous engagement with saidfollower means and arranged to actuate said follower means by coactionbetween said follower means and the interruption of said hub portion,whereby said unitary switch actuating member performs three operatingfunctions in said control, serving as a ratchet wheel, a switchactuating member and a rotatable bearing axle.

5. A refrigerator control comprising a snap acting switch member movablebetween two operating positions, a follower cooperating with said switchmember and acting thereupon for moving said switch member between itsoperating positions, a molded insulating base for supporting andcontaining said switch, a unitary rotatably switch actuating member oftripartite construction, said unitary actuating member including aratchet wheel portion, a hub portion with a periperal interruptionformed thereon, and an axle means, said portions being concentricallyarranged for rotation upon said axle means, stationary bearing means forrotatably supporting said axle means formed in said molded insulatingbase, means for intermittently driving said switch actuating member,said ratchet wheel portion having a toothed peripery driven by saiddriving means thereby to rotate said member, said follower beingsupported in cantilever fashion at one of its ends and having its freeend biased radially toward the axis of rotation of said actuatingmember, said hub portion being in continuous engagement with the freeend of said follower and arranged to actuate said follower by coactionbetween the free end of said follower and the interruption of said hubportion, whereby said unitary switch actuating member serves as acombination ratchet wheel, switch actuating element, and rotatablejournal.

6. A refrigerator control comprising an elongated leaf spring memberpivotally supported at the center thereof, said spring member having amovable contact at one of its ends and 'a tongue formed at the other endthereof, a follower disposed in partially overlying relationship to saidspring member, said follower being supported in cantilever fashion atone of its ends and having an actuating tooth formed at the other endthereof, a raised tab formed in said follower intermediate its ends,saidtab having a slot formed therein which receives the tongue of saidleaf spring member thereby to impart pivotal motion from said followerto said spring member for moving said spring member between twooperating positions, a rotatable switch actuating member of tripartiteconstruction, said actuating member including a ratchet wheel portion, ahub portion with a peripheral interruption formed thereon, and an axlemeans, said portions being concentrically arranged for rotation uponsaid axle means, stationary bearing means for rotatably supporting saidaxle means, means for intermittently driving said switch actuatingmember, said ratchet wheel portion having a toothed periphery driven bysaid driving means thereby to rotate said member, the actuating tooth ofsaid follower being biased radially toward the axis of rotation of saidactuating member, said hub portion being in continuous engagement withthe tooth of said follower and arranged to actuate said follower bycoaction between the tooth of said follower and the interruption of saidhub portion, whereby said switch actuating member serves as acombination ratchet wheel, switch actuating element, and rotatablejournal.

7. A refrigerator oontrol comprising an elongated leaf spring memberpivotally supported at the center thereof, said spring member having amovable contact at one of its ends and a tongue formed at the other endthereof, fixed contact means engageable by said movable contact,

' a follower disposed in partially overlying relationship to said springmember, said follower being supported in cantilever fashion at one ofits ends and having an aciii tuating tooth formed at the other endthereof, an upright tab formed in said follower intermediate its ends,said tab having a slot formed therein which receives the tongue of saidleaf spring member thereby to impart pivotal motion from said followerto said spring member for moving said movable contact between first andsecond operating positions, a rotatable switch actuating member, saidactuating member including a ratchet wheel portion, a hub portion with aperipheral interruption formed thereon, and an axle means, said portionsbeing concentrically arranged for rotation upon said axle means,stationary bearing means for rotatably supporting said axle means, meansfor intermittently driving said s 'itch actuating member, said ratchetwheel portion having a toothed periphery driven by said driving meansthereby to rotate said actuating member, the actuating tooth of saidfollower being biased radially toward the axis of rotation of saidactuating member, said hub portion being in continuous engagement withthe tooth of said follower and arranged to actuate said follower andmove said movable contact to its first operating position upon coactionbetween the tooth of said follower and the interruption of said hubportion, and a condition responsive means engageable with said followerwhen said movable contact is in the first position and arranged toactuate said follower and move said movable contact to its secondoperating position in response to a predetermined condition.

8. A refrigerator control comprising a switch movable between twooperating positions, follower means for moving said switch between itsoperating positions, a unitary rotatable switch actuating member fortripartite construction, said unitary member including a ratchet wheelportion, a hub portion with an axially extending peripheral interruptionformed thereon, and an axle means, said portions being concentricallyarranged for rotation upon said axle means, said ratchet wheel portionhaving a toothed periphery thereon, a driving member supported at one ofits ends in cantilever fashion, said driving member having a pawl meansthereon, said pawl means being arranged to intermittently engage thetoothed periphery of said ratchet wheel portion as said driving memberpivots upon its supported end, a solenoid means coacting with saiddriving member and arranged to step said driving member upondeenergization of said solenoid means thereby to rotate said switchactuating member, said hub portion being in continuous engagement withsaid follower means and arranged to actuate said follower means onceduring each revolution by coaction between said follower means and theinterruption of said hub portion, whereby said unitary switch actuatingmember serves as a ratchet wheel driven by said solenoid means, a switchactuatinelement cooperating with said follower, and an axle forrotatably supporting said unitary switch actuating member.

9. A refrigerator control comprising a switch movable between twooperating positions, follower means for moving said switch between itsoperating positions, a unitary rotatable switch actuating member oftripartite construction, said unitary member including a ratchet wheelportion, a hub portion with an axially extending peripheral interruptionformed thereon, and an axle means, said portions being concentricallyarranged for rotation upon said axle means, said ratchet wheel portionhaving a toothed periphery thereon, a driving member supported at one ofits ends in cantilever fashion, said driving member having a pawl meansthereon, said pawl means being arranged to intermittently engage thetoothed periphery ofsaid ratchet wheel portion as said driving memberpivots upon its supported end, a plunger ooacting with said drivingmember and arrange/J to step said driving member thereby to rotate saidactuating member upon its axle means, said hub portion being incontinuous engagement with said follower means and arranged to actuatesaid follower means once during each revolution by coaction between saidfollower means and the interruption of said hub portion, whereby saidunitary switch actuating member serves as a ratchet wheel driven by saidplunger, a switch actuating element cooperating with said follower, andan axle for rotatably supporting said unitary switch actuating member.

10. A refrigerator control comprising a switch movable between twooperating positions, follower means for moving said switch between itsoperating positions, a unitary rotatable switch actuating member oftripartite construction, said unitary member including a ratchet wheelportion, a hub portion with a peripheral interruption formed thereon,and an axle means, said portions being concentrically arranged forrotation upon said axle means, stationary bearing means for rotatablysupporting said axle means, said ratchet wheel portion having a toothedperiphery thereon, a driving member supported at one of its ends incantilever fashion, said driving member having a pawl means thereon, thepawl means of said driving member being in the configuration of aU-shaped hairpin, a bight portion of said pawl means being arranged tointermittently engage the toothed periphery of said ratchet wheelportion as said driving member pivots upon its supported end, thereby torotate said unitary actuating member, said hub portion being incontinuous engagement with said follower means and arranged to actuatesaid follower means by coaction between said follower means and theinterruption of said hub portion, whereby said unitary switch actuatingmember serves as a combination ratchet wheel, switch actuating element,and rotatable journal.

11. A refrigerator control comprising a snap acting switch membermovable between first and second operating positions, a followerengaging said switch member for moving said switch member between itsoperating positions, said follower being supported in cantilever fashionat one of its ends, having a projection formed at the other end andincluding a threaded recess between its ends, a rotatable switchactuating member with an interruption formed thereon, said interruptionbeing engaged by said follower for operating said switch member to itsfirst position, means for intermittently driving said switch actuatingmember in response to the cyclic operation of an external device, and acondition responsive means disposed in threaded relationship with therecess of said follower and engaged therewith when said switch member isin its first position for operating said switch member to its secondposition.

12. A refrigerator control comprising a snap acting switch membermovable between first and second operating positions, follower meansengaging said switch member for moving said switch member between itsoperating positions, said follower means being supported in cantileverfashion at one of its ends, having a projection formed at the other endthereof and including a threaded recess disposed between the ends, arotatable switch actuating member engaged by the projection of saidfollower means for operating said switch member to its first position,means for intermittently driving said switch actuating member inresponse to the cyclic operation of an external device, and a conditionresponsive means disposed in adjustable relationship with the recess ofsaid follower means and engaged therewith when said switch member is inits first position for operating said switch which receives theprojection of said follower for operating said switch member to itsfirst position at a predetermined rotative position of said actuatingmember, means for intermittently driving said switch actuating member inresponse to the cyclic operation of an external device, conditionresponsive means disposed in manually adjustable relationship to saidfollower and engaged therewith when said switch member is in its firstposition for operating said switch member to its second position, andmeans for adjusting the position of the support for said switch memberand said follower to assure that said switch member will not reach itssecond position until the projection of said follower has beendisengaged from the interruption of said actuating member and saidactuating member has been driven by said driving means from saidpredetermined relative position.

14. The refrigerator control of claim 13 wherein the conditionresponsive means includes a manually adjustable screw disposed inthreaded engagement with said follower, said screw having a pointedbottom, a bellows underlying the bottom of said screw, and a pushrodacted upon by said bellowsand in swivelling engagement with the pointedbottom of said screw thereby to transmit condition responsive force fromsaid bellows to said follower.

References Cited by the Examiner UNITED STATES PATENTS 2,711,079 6/55Grimshaw 20061.69 2,721,914 10/55 Cheltz 200 2,724,024 11/55 Durant etal 200-105 2,828,391 3/58 Slonneger 200 2,943,512 7/60 Nicolaus 74-5753,084,239 4/ 63 Horvath et a1 200-l56 BERNARD A. GILHEANY, PrimaryExaminer.

MAX L. LEVY, Examiner.

1. A REFRIGERATOR CONTROL COMPRISING A SWITCH MOVABLE BETWEEN TWOOPERATING POSITION, FOLLOWER MEANS FOR MOVING SAID SWITCH BETWEEN ITSOPERATING POSITIONS, A UNITARY ROTATABLE SWITCH ACTUATING MEMBER OFTRIPARTITE CONSTRUCTION, SAID MEMBER INCLUDING A RATCHET WHEEL PORTION,A HUB PORTION WITH AN AXIALLY EXTENDING PERIPHERAL INTERRUPTION FORMEDTHEREON, AND AN AXLE MEANS, SAID PORTIONS BEING CONCENTRICALLY ARRANGEDFOR ROTATION UPON SAID AXLE MEANS, MEANS FOR INTERMITTENTLY DRIVING SAIDSWITCH ACTUATING MEMBER, SAID RATCHET WHEEL PORTION HAVING A TOOTHEDPERIPHERY DRIVEN BY SAID DRIVING MEANS THEREBY TO ROTATE SAID ACTUATINGMEMBER, SAID HUB PORTION BEING IN CONTINUOUS ENGAGEMENT WITH SAIDFOLLOWER MEANS AND ARRANGED TO ACTUATE SAID FOLLOWER MEANS ONCE DURINGEACH REVOLUTION BY COACTION BETWEEN SAID FOLLOWER MEANS AND THEINTERRUPTION OF SAID HUB PORTION, WHEREBY SAID UNITARY SWITCH ACTUATINGMEMEBER SERVES AS A COMBINATION RATCHET WHEEL, SWITCH ACTUATING ELEMENT,AND ROTATABLE JOURNAL.